Chantilly weather in December

In December, Chantilly sees average daytime highs of 46°F and overnight lows near 32°F, with 3.5 in of precipitation across 9.1 wet days and about 9.3 hours of daylight. It is the 10th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 49°F in the first days to 44°F by the end. The sky is clear or mostly clear about 33% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of December to 9 h 18 min by month's end. Set against the rest of the year, December is Chantilly's 6th-clearest and 5th-windiest month. For the whole year in context, see Chantilly's year-round climate.

Daytime high
46°
10th warmest
Overnight low
32°
3rd coldest
Precipitation
3.5 in
9.1 wet days
Daylight
9 h 18 min
7:27 AM – 4:45 PM
Cloud cover
59%
6th clearest
Wind
7 mph
5th windiest
Solar energy
1.95 kWh/m²
Travel score
1.3
out of 10

Chantilly is unincorporated community located in Northern Virginia, United States.

Density
733/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 49°F in the first days to 44°F by the end.

A typical December day in Chantilly reaches about 46°F in the afternoon and slips back to 32°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 34°F and 59°F. Set against its neighbours, December runs about 9°F cooler than November and about 4°F warmer than January.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
15035
25035
34934
44934
54934
64833
74833
84733
94733
104733
114632
124632
134632
144632
154632
164531
174531
184531
194531
204531
214531
224531
234530
244530
254430
264430
274430
284430
294430
304430
314430

How December really feels in Chantilly

Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
31
wind chill below the day's low

The story in December is cold — wind chill drags the overnight "feels like" below the raw low.

Chantilly weather by month

How December compares with the rest of the year at a glance. December is the 10th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan42° / 28°3.08.639.60.3
Feb45° / 29°2.88.1310.51.1
Mar54° / 36°3.810211.73.3
Apr66° / 46°3.410.30.1135.8
May74° / 56°3.811.3014.16.5
Jun83° / 65°3.411.2014.75.5
Jul88° / 69°3.911.8014.44.4
Aug85° / 68°3.310.4013.55.1
Sep78° / 60°4.49.5012.36.7
Oct67° / 49°3.47.80116.5
Nov55° / 38°3.07.60.39.93.9
Dec46° / 32°3.59.12.19.31.3

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 53%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24852
34753
44753
54654
64654
74654
84555
94456
104456
114555
124555
134555
144555
154654
164654
174555
184555
194852
204753
214852
224852
234852
244852
254852
264852
274852
284753
294753
304753
314753

Chance of precipitation in December

Any precipitationSnow

Chantilly gets around 3.5 in of rain and snow over 9.1 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 30% and peaks near 32% on the wettest days, and about 2 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1304
2304
3305
4305
5316
6316
7316
8317
9317
10328
11328
12318
13318
14318
15318
16318
17318
18307
19307
20297
21297
22287
23287
24276
25276
26276
27276
28276
29276
30276
31287

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19730
29730
39820
49820
59820
69820
79820
89910
99910
109910
119910
129910
139910
149910
159910
169910
179910
189910
199910
209910
219910
229910
239910
249910
259910
269910
279910
289910
299910
309811
319811

Wind in December

Winds average 7 mph in December.

Across December, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 30 min at the start of December to 9 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:15 AM to 7:34 AM, and sunset from 4:44 PM to 4:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:154:44
29.57:164:44
39.47:174:43
49.47:184:43
59.47:194:43
69.47:204:43
79.47:214:43
89.47:214:43
99.37:224:43
109.37:234:43
119.37:244:43
129.37:254:44
139.37:254:44
149.37:264:44
159.37:274:44
169.37:274:45
179.37:284:45
189.37:284:45
199.37:294:46
209.37:304:46
219.37:304:46
229.37:314:47
239.37:314:47
249.37:314:48
259.37:324:48
269.37:324:49
279.37:334:50
289.37:334:50
299.37:334:51
309.37:334:51
319.37:344:52

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 1.95 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 1.95 kWh/m² to a high of 6.15 kWh/m² in June across the year — December's 1.95 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.1Moderate
22.0Moderate
32.0Moderate
42.0Moderate
52.0Moderate
62.0Dim
72.0Dim
81.9Dim
91.9Dim
101.9Dim
111.9Dim
121.9Dim
131.9Dim
141.9Dim
151.9Dim
161.9Dim
171.9Dim
181.9Dim
191.9Dim
201.9Dim
211.9Dim
221.9Dim
231.9Dim
241.9Dim
251.9Dim
262.0Dim
272.0Dim
282.0Dim
292.0Dim
302.0Dim
312.0Dim
Planning a trip in December

Is December a good time to visit Chantilly?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

1.3
Sightseeing
10th-best month of the year
0.0
Beach & pool
10th-best month of the year

December is a weaker month for outdoor sightseeing in Chantilly.

What to pack for Chantilly in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Chantilly sees daytime highs around 46°F and nights near 32°F. Pack a warm layer. Worth having: a heavy coat and rain gear. About 9 days see rain.

a warm layera heavy coatrain gear

UV index in Chantilly in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Chantilly peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5High
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Chantilly in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Chantilly is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 129 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb12Moderate
Mar13Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Moderate
Oct9Good
Nov9Good
Dec10Good
Location & terrain

Where is Chantilly?

Chantilly sits at 38.9°N, 77.4°W, 322 ft above sea level, in United States. The nearest listed city is Oak Hill, 2.5 mi away.

Topography around Chantilly

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Chantilly.

Within 2 miles, the terrain around Chantilly has only modest variations in elevation — a maximum elevation change of 180 ft around an average of 328 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 768 ft; within 50 miles, large variations in elevation — a maximum elevation change of 3,609 ft.

The land around Chantilly is covered by trees (51%) and artificial surfaces (34%) within 2 miles, trees (67%) within 10 miles, and trees (66%) within 50 miles.

2 miles
180 ft
10 miles
768 ft
50 miles
3,609 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
December weather nearby: Oak Hill 2.5 mi · Centreville 3.7 mi · South Riding 4.3 mi · Herndon 5.6 mi · Reston 6.8 mi · Oakton 6.8 mi · Fairfax 7.5 mi · Sterling 7.5 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Chantilly (38.8943°, -77.4311°, elevation 322 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).